1. Field of the Invention
The present invention relates to a method for cleaning and sterilizing medical equipment after use. The target objects for this invention are fiberscopes, such as gastrocameras and other types of endoscopes, including peritoneoscopes, thoracoscopes and arthoroscopes, and medical supplies, such as catheters and tubes, that have long ducts or hollow portions and that tend to be repetitively employed by being introduced into human bodies.
2. Related Arts
Because of the need to prevent nosocomial bacterial or viral infections and mechanical accidents, and for economic reasons, inexpensive medical products, such as syringes, hypodermic needles and instillators, in most cases are classified as disposable materiel and are used only once and then discarded as infective waste. However, fiberscopes such as gastrocameras and other types of endoscopes, including peritoneoscopes, thoracoscopes and arthoroscopes, and other expensive medical products, like catheters and similar intubation equipment, must in principle be employed repetitively. And due to the necessity to prevent infection, each time these medical devices are used they must be thoroughly cleaned by hand, or in an automatic washer, and must thereafter be dried, deodorized and sterilized.
This type of medical equipment, epitomized by a fiberscope having a hollow portion or a narrow duct (a channel) that serves as a flow path for mucus or fluids or as an insertion path for forceps, for example, is a device that is extremely difficult to thoroughly clean and disinfect. Traditionally, to clean, deodorize, and sterilize such a medical device, the subsequently described disinfection and sterilization method has been widely employed. According to this method, ultrasonic cleaning is employed to clean the exterior surface of a device, and various types of cleaning fluids are used, as needed, to clean the inner wall of a duct or a hollow portion. Then, the device is sterilized by wiping it with ethanol, employed as a disinfectant, a fourth ammonium disinfectant, an iodine disinfectant or an aldehyde disinfectant, or by being immersed in various types of disinfectants, or gas sterilization is used for which the device is retained in a closed atmosphere, such as formalin gas or ethylene oxide gas.
According to this method, however, an extended time is required for deodorization and sterilization, so that a device for which such processing is performed can not be used frequently. Further, when a complicated cleaning device is employed, costs involved in its use are greatly increased. Other available methods are EOG sterilization and thermal sterilization, for which an autoclave is used; however, it is known that with these methods sterilization failures occur when air remains in a duct or a hollow portion. As a result, there is a demand for a drying, deodorization and sterilization method and apparatus that can safely, easily and completely deodorize and sterilize medical devices such as are described above.
To this end, it is well known that a chlorine dioxide solution, or gas, has a strong bleaching action and is an appropriate deodorization and sterilization agent, and many manufacturing methods have been proposed for employing this agent.
However, industrially produced high-density chlorine dioxide is a strong oxidizing agent, and can react with other materials and generate high-density chlorine. Further, it presents a slight possibility of an explosion. Because of these properties, a 5% solution of “stabilized chlorine dioxide”, developed by International Dioxide Inc., has been provided as a chlorine dioxide that is less dangerous and easier to handle. This solution may be employed as a chlorine dioxide solution after it has been diluted, as needed, to a proper density.
A safe chlorine dioxide gas, which has no sharp or pungent odor, is obtained by vaporizing stabilized chlorine dioxide, and when brought into contact with a target device, provides various effects, including excellent deodorization, disinfection and sterilization. With this gas, the pasteurization of various viruses, bacteria, molds and pathogens and sterilization are performed extremely effectively, and can be completed within a short period of time. Further, great deodorization effects are also obtained, and chemical product and putrefaction odors are effectively removed. Further, the propagation of microorganisms that cause bad odors can be prevented.
As a deodorization and disinfection method and apparatus that use chlorine dioxide, proposed are a method and an apparatus (Japanese Unexamined Patent Publication No. 2002-306577) wherein an object to be disinfected is placed in a closed space, and is deodorized and disinfected by spraying a chlorine dioxide solution mist into this space. When this process is employed, however, it is difficult to completely deodorize and disinfect a medical device that has a duct or a hollow portion.
The present inventor has also proposed a method and an apparatus for providing the above effects by irradiating a gel of a stabilized dioxide solution with an ultraviolet beam to supply a deodorization and sterilization gas (Japanese Unexamined Patent Publication No. 2000-202009); and a method whereby a target device is immersed in a stabilized chlorine dioxide solution in a container that is filled with a gas generated from the stabilized chlorine dioxide, so as to deodorize and sterilize the object retained in the container (Japanese Unexamined Patent Publication No. 2001-29440). However, with these methods it is also difficult to deodorize and disinfect a medical device that has been used and that has a duct or a hollow portion. The present inventor, therefore, studied and conducted experiments to devise a method for cleaning, deodorizing and sterilizing medical devices after use, such as gastrocameras and other endoscopes, that have long ducts or hollow portions, and finally is able to provide the present invention.